For dual-purpose photo/visual scopes, a “VISA” adapter (Visual / Imaging System Adapter) accepts the tunable top from the standard Tele Vue 2″ Paracorr Type-2. The 2″ format is fine visually since secondary mirror size limits maximum exit pupil diameter to around 7mm. The widest true field eyepiece choice with an f/3 (f/3.45 when used with Paracorr) is, therefore, Tele Vue’s own 21mm Ethos which delivers a 6.1mm exit pupil at f/3.45.
Tele Vue Visual / Imaging System Adapter (VISA)
Visual Use
For dual-purpose photo/visual scopes, a “VISA” adapter (Visual / Imaging System Adapter) accepts the tunable top from the standard Tele Vue 2″ Paracorr Type-2. The 2″ format is fine visually since secondary mirror size limits maximum exit pupil diameter to around 7mm. The widest true field eyepiece choice with an f/3 (f/3.45 when used with Paracorr) is, therefore, Tele Vue’s own 21mm Ethos which delivers a 6.1mm exit pupil at f/3.45.
Imaging with DSLR or CCD Cameras
If you have a 35mm format DLSR or CCD camera, the “VISA” adapter accepts Tele Vue Imaging System accessories.
